I'm a former FB eng and a Xoogler and have been an interviewer at both places. The recruiter sets the level for your interviews. There's an option for the inter

I'm a former FB eng and a Xoogler and have been an interviewer at both places. The recruiter sets the level for your interviews. There's an option for the interviewer to recommend you for a higher level, but there's no incentive for the interviewer to do so and is almost never used. Getting higher rating from the interviews will only make the hiring committee's decision to hire you easier, and almost never affects your levelling.